¼ cup (56g) unsalted butter, softened 2/3 cup (117g) light brown sugar, packed 1 egg, lightly beaten 2 teaspoons vanilla extract 1 cup (140g) all purpose flour ½ teaspoon baking soda ¼ teaspoon salt 200g milk Toblerone, roughly chopped
Preheat the oven to 180°C/350°F; line two large baking sheets with baking paper. Cream the butter with the sugar until light and fluffy. Beat in the egg and vanilla extract until the mixture is smooth, then stir in the flour, baking soda, salt and 150g Toblerone. Drop leveled tablespoons of dough onto each sheet, 5cm (2in) apart. Press the remaining chopped Toblerone over the surface of the cookies. Bake for 10-12 minutes, just until dry-looking and covered with even cracks but not quite firm to the touch. Leave to cool and firm up on the baking sheets for a few minutes before carefully peeling away from the paper.
The cookies will keep in an airtight tin for up to 3 days.